For large-screen liquid crystal displays (LCDs), high contrast ratio, fast response time, wide viewing angle, and excellent color performance such as small color shift and good angular-dependent color uniformity all have to be satisfied simultaneously. The vertical alignment (VA) technology as one of the mainstream LCD TV technologies has been widely investigated and developed. The normally black VA LCDs exhibit an excellent contrast ratio at normal incident angle. The response time issue can be solved with the overdrive and undershoot approach describe in S. T. Wu, “Nematic liquid crystal modulator with response time less than 100 μs at room temperature”, Appl. Phys. Lett., Vol. 57, p. 986, (1990).
To achieve a wide viewing angle, the formation of multi-domain vertical alignment (MVA) under the external electric fields is critically required. Currently, four-domain and eight-domain VA LC configurations are commonly practiced by the adoption of protrusions or slits on the device substrates. With the help of the optimized compensation films, the viewing angle of a typical MVA-LCD can reach above 100:1 at the ±80° viewing cone as described in Q. Hong et al., “Extraordinarily-high-contrast and wide-view liquid crystal displays”, Appl. Phys. Lett., vol. 86, p. 121107 (2005). Meanwhile, compared with the in-plane switching (IPS) mode, the color performance in the color shift and angular color uniformity of VA mode is a little inferior, which usually shows an evident gamut curve distortion at the large oblique viewing angles as described in H. C. Jin, et al., “Development of 100-in. TFT-LCDs for HDTV and public-information-display applications”, Journal of the SID, vol. 15, p. 277 (2007).
Some methods have been proposed to improve the gamma curve of VA mode LCDs. From the panel driving point, the dynamic correction of LCD gamma curve approach has been described in U.S. Pat. No. 6,256,010 B1 issued to Y. C. Chen et al. in 2001 and U.S. Pat. No. 7,164,284 B2 issued to H. Pan et al. in 2007. On the contrary, its effectiveness in reducing the gamma curve at the oblique viewing angle is questionable. From the panel design point, a capacitive coupled (CC) method is disclosed in U.S. Pat. No. 7,158,201 B2 issued to by H. S. Kim et al in 2007, and a two-TFT approach is proposed to produce eight domains as published by S. S. Kim in SID'05 Symposium Digest, p. 1842-1847, and by C. C. Liu et al in Int'l Display Workshops, p. 625-626 (2006). Although the abovementioned methods can improve the corresponding angular-dependent gamma curves, they require complex electronic circuits. In addition, the manufacturing cost and device power consumption increase when two TFTs are used in a unit pixel.